SILICON CARBIDE SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD FOR SAME

摘要

Provided is a silicon carbide semiconductor device capable of mitigating an electric field in a protective diffusion layer formed in lower portions of trenches. A silicon carbide semiconductor device (100) is provided with: a drift layer (2a) of a first conductivity type; source regions (4) of the first conductivity type, which are formed in upper portions within a semiconductor layer (2); trenches (5a) which are formed so as to extend through the source regions (4) and a base region (3); edge termination trenches (5b) which are formed around the trenches (5a); a gate dielectric film (6) which is formed on the bottom surface and the side surfaces of the trenches (5a); gate electrodes (7) which are formed so as to be buried within the trenches (5a) across the gate dielectric film (6); a protective diffusion layer (13) of a second conductivity type, which is formed in the lower portions of the trenches (5a) and for which an impurity concentration of a second conductivity type is a first impurity concentration; and a termination diffusion layer (16) of the second conductivity type, which is formed in the lower portions of the edge termination trenches (5b) and for which an impurity concentration of a second conductivity type is a second impurity concentration that is lower than the first impurity concentration.